An epoxy resin has been widely used for printing circuit boards due to its properties. The epoxy resin has also been investigated to comply with high density requirements associated with the recent development in reduction in size and weight.
In particular, as is found in a build-up circuit board, a plating resist that remains as an insulating layer in a printing circuit board is required to have high glass transition temperature, volumetric specific resistance, mechanical properties, and low water absorption capable of coping with heat generation from wirings highly integrated, thinning of insulating layers, and lowering in adhesion between conductive layers and insulating layers.
Further, the epoxy resin that is used for prepregs or the like is conventionally admixed with various kinds of inorganic fillers so as to reduce linear expansion and to prevent thermal deformation. However, it is difficult to admix inorganic fillers, since the inorganic fillers admixed with the epoxy resin sometimes lower the tensile strength or elongation, or impair the reliability of the circuitries by short-circuit caused by aggregation.
In relation to the epoxy resin, a hardened material prepared from 2,2-bis(3,4-epoxycyclohexyl)propane and an acid anhydride is disclosed in Patent Document 1. Further, Patent Documents 2, 3, and 4 disclose an epoxy resin that is admixed with a polyamide having a phenolic hydroxyl group.
The epoxy resin disclosed in Patent Documents 2 and 3 is the one that is separately admixed with a hardener. The polyamide having a phenolic hydroxyl group disclosed in Patent Document 4 has a molecular structure that is derived from an aromatic dicarboxylic acid having a hydroxyl group as a source material. There is no specific description about the compound of the present invention that is obtained with using an aromatic diamine having a hydroxyl group as a source material. There is also no description about a specific effect on the linear expansion coefficient.
Patent Document 1: DE 107,798
Patent Document 2: Claims, and Examples described from page 6, line 40 on the left column to the end of page 8 of Japanese Patent Laid-Open Publication No. 2001-31784
Patent Document 3: Claims of Japanese Patent Laid-Open Publication No. 2001-49082
Patent Document 4: Claims of Japanese Patent Laid-Open Publication No. 2005-29720